Stock-Based Compensation Plans (Summary of Restricted Stock and Stock Option Activity) (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, at beginning of period, Number of Shares	2,325,797
Options granted, Number of Shares	0
Exercised options, Number of Shares	(108,841)
Options forfeited or expired, Number of Shares	(94,380)
Options outstanding, at end of period, Number of Shares	2,122,576
Options exercisable, at end of period, Number of Shares	1,814,294
Options expected to vest, at end of period, Number of Shares	294,667
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Options, at beginning of period, Weighted-average Exercise Price (in dollars per share)	$ 26.97
Options granted, Weighted-Average Exercise Price (in dollars per share)	$ 0.00
Options exercised, Weighted-Average Exercise Price (in dollars per share)	$ 15.98
Options forfeited, Weighted-Average Exercise Price (in dollars per share)	$ 35.30
Options, at end of period, Weighted-average Exercise Price (in dollars per share)	$ 27.16
Options exercisable, at end of period, Weighted-Average Exercise Price (in dollars per share)	$ 27.83
Options expected to vest, at end of period, Weighted-Average Exercise Price (in dollars per share)	$ 23.24
Time Based Restricted Stock Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock, Outstanding at beginning of period	1,705
Restricted stock, Granted	13,678
Restricted stock, Vested restricted stock awards	(9,685)	[1]
Restricted stock, Forfeited	0
Restricted stock, Outstanding at end of period	5,698
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock, at beginning of period, Weighted-average Grant Date Fair Value (in dollars per share)	$ 22.75
Restricted stock, Granted	$ 29.34
Restricted stock, Vested restricted stock awards	$ 28.18	[1]
Restricted stock, Forfeited	$ 0.00
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share)	$ 29.34
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock, Outstanding at beginning of period	138,450
Restricted stock, Granted	146,248
Restricted stock, Vested restricted stock awards	(113,394)	[1]
Restricted stock, Forfeited	(16,909)
Restricted stock, Outstanding at end of period	154,395
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock, at beginning of period, Weighted-average Grant Date Fair Value (in dollars per share)	$ 24.43
Restricted stock, Granted	$ 29.94
Restricted stock, Vested restricted stock awards	$ 25.84	[1]
Restricted stock, Forfeited	$ 26.47
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share)	$ 28.40
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock, Outstanding at beginning of period	267,119
Restricted stock, Granted	215,412
Restricted stock, Vested restricted stock awards	(166,008)	[1]
Restricted stock, Forfeited	(21,941)
Restricted stock, Outstanding at end of period	294,582
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Restricted stock, at beginning of period, Weighted-average Grant Date Fair Value (in dollars per share)	$ 22.96
Restricted stock, Granted	$ 29.65
Restricted stock, Vested restricted stock awards	$ 24.68	[1]
Restricted stock, Forfeited	$ 25.27
Restricted stock, at end of period, Weighted-average Grant Date Fair Value (in dollars per share)	$ 26.71

[1] Vested for purposes of recording compensation expense.